(a(i))[2]
Which two factors can affect the energy needed for this promotion?
(b(i))[4]
A compound, $J$, has the formula $\text{C}_4\text{H}_{10}\text{O}$. Its NMR spectrum is shown. State the group responsible for each peak and hence deduce the structure of $J$. Peak at $\delta = 1.26$. Peak at $\delta = 2.0$. Structure of $J$.
(b(ii))[6]
There are three other isomers of $J$ with the same functional group as $J$. Draw two of those three isomers and show how many different chemical shifts each would produce in its NMR spectrum.
(c(i))[1]
Which element appears most strongly in the X-ray crystallography of a nucleic acid? Explain your answer.
(c(ii))[1]
Why will X-ray crystallography not detect hydrogen atoms? Explain why.